ABSTRACT
This chapter is an overview of anaerobic bacteria with a Tmax of 60°C or above and (except for one) with a Topt of 50°C or above. With a few exceptions, it contains mainly the organisms which have been either validly published in the Approved List or validated by inclusion in the Validation Lists. The first thermophilic anaerobe, which is still validly described is Clostridium thermocellum. The thermophilic sulfate reducers comprise a variety of different organisms. T. lactoethylicus is one of the few organisms among the thermophilic anaerobic bacteria which does not obligately require yeast extract or vitamins for growth on glucose. Thermoanaerobacter cellulotyticus is described under cellulolytic organisms. Similar to some of the other cellulolytic clostridia, their fermentation products resemble the mixed product type with ethanol, acetate, lactate, CO2, and H2 as products.
